HR: 0800h
AN: SM31A-0404    [Abstracts]
TI: Near-Earth Breakup Triggered by the Burst Flow.
AU: * Voronkov, I O
EM: igor@phys.ucalgary.ca
AF: University of Calgary, Department of Physics and Astronomy, University of Calgary, Calgary, Ab T2N 1N4 Canada
AU: Donovan, E F
EM: eric@phys.ucalgary.ca
AF: University of Calgary, Department of Physics and Astronomy, University of Calgary, Calgary, Ab T2N 1N4 Canada
AB: Auroral optical observations suggest that in some cases, a breakup at the inner edge of the plasma sheet occurs in association with earthward burst flows from more distant tail, but without direct flow intrusion in the region. Using an MHD model of the near-Earth plasma sheet, a possibility of such an interaction was explored and the following possible scenario was revealed. The near-dipolar magnetic field topology of the inner PS leads to the flow braking which in turn launches a wide spectrum of dispersive compressional waves propagating further Earthward. Strong topological variations of the magnetic field at the inner edge of the PS, required by the equilibrium conditions, play a role of the resonant cavity for selected compressional modes. Growing resonance modes provide a ponderomotive force pumping up corresponding nonlinear ballooning eigenmodes. The latter extract energy stored in the inner PS and produce vortical structures expanding tailward.
DE: 2704 Auroral phenomena (2407)
DE: 2752 MHD waves and instabilities (2149, 6050, 7836)
DE: 2753 Numerical modeling
DE: 2764 Plasma sheet
DE: 2790 Substorms
SC: SPA-Magnetospheric Physics [SM]
MN: Fall Meeting 2005